<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
  <meta charset="UTF-8">
  <title>JavaScript 数据类型</title>
</head>
<body>
<h2>空值</h2>
<p>空值与undefined不同，空的字符串变量既有值也有类型。</p>

<p id="demo"></p>

<script>
  var car = "";
  document.getElementById("demo").innerHTML =
          "其值是：" +
          car + "<br>" +
          "类型是：" + typeof car;
</script>
</body>
</html>

<!--
输出结果：
其值是：
类型是：string
-->